MDEV-22021: Galera database could get inconsistent with rollback to savepoint

When binlog is disabled, WSREP will not behave correctly when
SAVEPOINT ROLLBACK is executed and we will not rollback transaction.

mysql-test/suite/galera/r/MDEV-22021.result

+connection node_2;
+connection node_1;
+CREATE TABLE t1 (f1 INTEGER PRIMARY KEY);
+START TRANSACTION;
+INSERT INTO t1 VALUES (1);
+SAVEPOINT sp1;
+INSERT INTO t1 VALUES (2);
+ROLLBACK TO SAVEPOINT sp1;
+COMMIT;
+SELECT COUNT(*) = 1 FROM t1;
+COUNT(*) = 1
+1
+connection node_2;
+SELECT COUNT(*) = 1 FROM t1;
+COUNT(*) = 1
+1
+connection node_1;
+DELETE FROM t1;
+START TRANSACTION;
+SAVEPOINT sp1;
+INSERT INTO t1 VALUES (1);
+SAVEPOINT sp2;
+INSERT INTO t1 VALUES (2);
+ROLLBACK TO SAVEPOINT sp2;
+ROLLBACK TO SAVEPOINT sp1;
+COMMIT;
+SELECT COUNT(*) = 0 FROM t1;
+COUNT(*) = 0
+1
+connection node_2;
+SELECT COUNT(*) = 0 FROM t1;
+COUNT(*) = 0
+1
+connection node_1;
+DELETE FROM t1;
+START TRANSACTION;
+SAVEPOINT sp1;
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (2);
+INSERT INTO t1 VALUES (3);
+INSERT INTO t1 VALUES (4);
+SAVEPOINT sp2;
+INSERT INTO t1 VALUES (5);
+ROLLBACK TO SAVEPOINT sp2;
+INSERT INTO t1 VALUES (6);
+INSERT INTO t1 VALUES (7);
+ROLLBACK TO SAVEPOINT sp1;
+INSERT INTO t1 VALUES (8);
+COMMIT;
+SELECT COUNT(*) = 1 FROM t1;
+COUNT(*) = 1
+1
+connection node_2;
+SELECT COUNT(*) = 1 FROM t1;
+COUNT(*) = 1
+1
+DROP TABLE t1;

mysql-test/suite/galera/t/MDEV-22021.combinations

+[binlogoff]
+
+[binlogon]
+log-bin

mysql-test/suite/galera/t/MDEV-22021.test

+#
+# SAVEPOINT ROLLBACK can introduce inconsistency in cluster.
+#
+
+--source include/galera_cluster.inc
+
+CREATE TABLE t1 (f1 INTEGER PRIMARY KEY);
+
+START TRANSACTION;
+INSERT INTO t1 VALUES (1);
+SAVEPOINT sp1;
+INSERT INTO t1 VALUES (2);
+ROLLBACK TO SAVEPOINT sp1;
+COMMIT;
+
+SELECT COUNT(*) = 1 FROM t1;
+
+--connection node_2
+SELECT COUNT(*) = 1 FROM t1;
+
+--connection node_1
+DELETE FROM t1;
+
+START TRANSACTION;
+SAVEPOINT sp1;
+INSERT INTO t1 VALUES (1);
+SAVEPOINT sp2;
+INSERT INTO t1 VALUES (2);
+ROLLBACK TO SAVEPOINT sp2;
+ROLLBACK TO SAVEPOINT sp1;
+COMMIT;
+
+SELECT COUNT(*) = 0 FROM t1;
+--connection node_2
+SELECT COUNT(*) = 0 FROM t1;
+
+--connection node_1
+DELETE FROM t1;
+
+START TRANSACTION;
+SAVEPOINT sp1;
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (2);
+INSERT INTO t1 VALUES (3);
+INSERT INTO t1 VALUES (4);
+SAVEPOINT sp2;
+INSERT INTO t1 VALUES (5);
+ROLLBACK TO SAVEPOINT sp2;
+INSERT INTO t1 VALUES (6);
+INSERT INTO t1 VALUES (7);
+ROLLBACK TO SAVEPOINT sp1;
+INSERT INTO t1 VALUES (8);
+COMMIT;
+
+SELECT COUNT(*) = 1 FROM t1;
+
+--connection node_2
+SELECT COUNT(*) = 1 FROM t1;
+
+DROP TABLE t1;

mysql-test/suite/galera_sr/r/GCF-571.result

@@ -24,7 +24,7 @@ COUNT(*) > 0
 1
 SELECT COUNT(*) = 1 FROM mysql.wsrep_streaming_log WHERE frag LIKE '%SAVEPOINT `A`%';
 COUNT(*) = 1
-0
+1
 connection node_1;
 ROLLBACK TO SAVEPOINT A;
 connection node_1a;
@@ -36,7 +36,7 @@ COUNT(*) > 0
 1
 SELECT COUNT(*) = 1 FROM mysql.wsrep_streaming_log WHERE frag LIKE '%SAVEPOINT `A`%';
 COUNT(*) = 1
-0
+1
 SELECT COUNT(*) = 1 FROM mysql.wsrep_streaming_log WHERE frag LIKE '%ROLLBACK TO `A`%';
 COUNT(*) = 1
 0
@@ -49,7 +49,7 @@ COUNT(*) > 0
 1
 SELECT COUNT(*) = 1 FROM mysql.wsrep_streaming_log WHERE frag LIKE '%SAVEPOINT `A`%';
 COUNT(*) = 1
-0
+1
 SELECT COUNT(*) = 1 FROM mysql.wsrep_streaming_log WHERE frag LIKE '%ROLLBACK TO `A`%';
 COUNT(*) = 1
 0

mysql-test/suite/galera_sr/r/GCF-620.result

@@ -14,5 +14,5 @@ COMMIT;
 connection node_2;
 SELECT COUNT(*) = 2 FROM t1;
 COUNT(*) = 2
-0
+1
 DROP TABLE t1;

mysql-test/suite/galera_sr/r/galera_sr_rollback_savepoint.result

@@ -33,7 +33,7 @@ COUNT(*) = 5
 1
 SELECT COUNT(*) = 0 FROM t1 WHERE f2 = 'b';
 COUNT(*) = 0
-0
+1
 SELECT COUNT(*) = 5 FROM t1 WHERE f2 = 'c';
 COUNT(*) = 5
 1

mysql-test/suite/galera_sr/r/mysql-wsrep-features#22.result

@@ -31,5 +31,5 @@ COUNT(*) = 6
 connection node_2;
 SELECT COUNT(*) = 6 FROM t1;
 COUNT(*) = 6
-0
+1
 DROP TABLE t1;

sql/log.cc

@@ -2271,9 +2271,6 @@ static int binlog_savepoint_set(handlerton *hton, THD *thd, void *sv)
   int error= 1;
   DBUG_ENTER("binlog_savepoint_set");
 
-  if (wsrep_emulate_bin_log)
-    DBUG_RETURN(0);
-
   char buf[1024];
 
   String log_query(buf, sizeof(buf), &my_charset_bin);
@@ -2306,9 +2303,6 @@ static int binlog_savepoint_rollback(handlerton *hton, THD *thd, void *sv)
 {
   DBUG_ENTER("binlog_savepoint_rollback");
 
-  if (wsrep_emulate_bin_log)
-    DBUG_RETURN(0);
-
   /*
     Write ROLLBACK TO SAVEPOINT to the binlog cache if we have updated some
     non-transactional table. Otherwise, truncate the binlog cache starting
@@ -10798,18 +10792,20 @@ void wsrep_register_binlog_handler(THD *thd, bool trx)
     back a statement or a transaction. However, notifications do not happen
     if the binary log is set as read/write.
   */
-  //binlog_cache_mngr *cache_mngr= thd_get_cache_mngr(thd);
   binlog_cache_mngr *cache_mngr=
     (binlog_cache_mngr*) thd_get_ha_data(thd, binlog_hton);
   /* cache_mngr may be missing e.g. in mtr test ev51914.test */
-  if (cache_mngr && cache_mngr->trx_cache.get_prev_position() == MY_OFF_T_UNDEF)
+  if (cache_mngr)
   {
     /*
       Set an implicit savepoint in order to be able to truncate a trx-cache.
     */
-    my_off_t pos= 0;
-    binlog_trans_log_savepos(thd, &pos);
-    cache_mngr->trx_cache.set_prev_position(pos);
+    if (cache_mngr->trx_cache.get_prev_position() == MY_OFF_T_UNDEF)
+    {
+      my_off_t pos= 0;
+      binlog_trans_log_savepos(thd, &pos);
+      cache_mngr->trx_cache.set_prev_position(pos);
+    }
 
     /*
       Set callbacks in order to be able to call commmit or rollback.

sql/wsrep_high_priority_service.cc

@@ -453,11 +453,15 @@ Wsrep_applier_service::Wsrep_applier_service(THD* thd)
   thd->wsrep_cs().open(wsrep::client_id(thd->thread_id));
   thd->wsrep_cs().before_command();
   thd->wsrep_cs().debug_log_level(wsrep_debug);
-
+  if (!thd->slave_thread)
+    thd->system_thread_info.rpl_sql_info=
+      new rpl_sql_thread_info(thd->wsrep_rgi->rli->mi->rpl_filter);
 }
 
 Wsrep_applier_service::~Wsrep_applier_service()
 {
+  if (!m_thd->slave_thread)
+    delete m_thd->system_thread_info.rpl_sql_info;
   m_thd->wsrep_cs().after_command_before_result();
   m_thd->wsrep_cs().after_command_after_result();
   m_thd->wsrep_cs().close();

sql/wsrep_thd.cc

@@ -53,11 +53,6 @@ static void wsrep_replication_process(THD *thd,
 
   Wsrep_applier_service applier_service(thd);
 
-  /* thd->system_thread_info.rpl_sql_info isn't initialized. */
-  if (!thd->slave_thread)
-    thd->system_thread_info.rpl_sql_info=
-      new rpl_sql_thread_info(thd->wsrep_rgi->rli->mi->rpl_filter);
-
   WSREP_INFO("Starting applier thread %llu", thd->thread_id);
   enum wsrep::provider::status
     ret= Wsrep_server_state::get_provider().run_applier(&applier_service);
@@ -68,8 +63,6 @@ static void wsrep_replication_process(THD *thd,
   mysql_cond_broadcast(&COND_wsrep_slave_threads);
   mysql_mutex_unlock(&LOCK_wsrep_slave_threads);
 
-  if (!thd->slave_thread)
-    delete thd->system_thread_info.rpl_sql_info;
   delete thd->wsrep_rgi->rli->mi;
   delete thd->wsrep_rgi->rli;